Abstract
4H-SiC lateral NMOSFETs on p--type epitaxial layer were fabricated and studied. In order to avoid high interface states (Dit) caused by carbon cluster near the SiO2/4H-SiC interface and to enhance Field- Effect Mobility (μFE), we choose Atomic-Layer-Deposition (ALD) Al2O3 to be the critical gate insulator. The measured maximum μFE is about 130 cm2/Vs by analyzing I-V characteristics. We also fabricated MIS capacitor with Al2O3 as the insulator on p-type silicon substrate, and investigated the improvement of Al2O3 quality by annealing in oxygen with different temperature. C-V and I-V measurements indicated the best annealing temperature is between 400~500℃. Wide band gap materials with high breakdown electric field are needed for high-power semiconductor devices. 4H-SiC vertical Schottky Barrier Diode (SBD) on n--type epitaxial layer were also studied and fabricated in this thesis. The structure of the device is Trench-Field Plate SBD (TFPSBD) that we designed with simulation tools. The measured ideal factor is 1.08~1.2, The Ron,sp of 50 μm diameter diode is 2.5 mΩ*cm2, and the best breakdown voltage is 940 V.